Unidirectional freezing freeze-thaw cycle triaxial apparatus and test method thereof

Abstract

The invention discloses a unidirectional freezing freeze-thaw cycle triaxial apparatus which comprises a pressure chamber, a mainframe, a stable air pressure source, a temperature control system, a water replenishing device and a test and data acquisition system, wherein the pressure chamber comprises an external pressure chamber and an internal pressure chamber; the upper part of the internal pressure chamber is provided with a sample cap formed by an upper box of the sample cap and a lower box of the sample cap; the bottom of the pressure chamber is provided with a base formed by an upper box of the base and a lower box of the base; the sample cap, the base and the external pressure chamber are respectively connected with a refrigerating machine by a heat insulation pipeline; the upper part of the pressure chamber is provided with a load power transmission shaft which passes through an upper cover of the pressure chamber and acts on the upper box of the sample cap; the base of the pressure chamber is connected with the water replenishing device by a pipeline; the mainframe is used for providing power for cutting a sample; and a temperature sensor arranged on the refrigerating machine and a displacement sensor and a load sensor which are arranged on the mainframe are connected with the test and data acquisition system. The unidirectional freezing freeze-thaw cycle triaxial apparatus can realize the unidirectional freezing freeze-thaw cycle test under the conditions of low temperature and water supplement, and meanwhile can be used for testing the triaxial strength under the freeze-thaw cycle condition.

Description

technical field [0001] The invention relates to the technical field of rock and soil mechanics and engineering testing, in particular to a unidirectional freezing-thawing cycle triaxial instrument and a testing method. The invention can realize the one-way freezing test and the freeze-thaw cycle test under the condition of low-temperature replenishment, and simultaneously test the triaxial strength under the condition of freeze-thaw cycle. Background technique [0002] The distribution area of ​​seasonal frozen soil in my country is very extensive, covering areas with latitude higher than 24°, and its distribution area is 5.137×106km 2 , accounting for 53.5% of the country's land area. The foundation soil of industrial and civil buildings, canals, culverts, roads and bridges in the seasonally frozen soil area changes with the alternation of winter and summer, and the soil freezes and thaws. This phenomenon is called a freeze-thaw cycle. During the freezing process, the phy...

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Problems solved by technology

In 2004, Chang Xiaoxiao and others proposed a low-temperature and high-pressure triaxial creep tester (see Chinese Patent No. "ZL200420085815.6" for details), which uses a three-way freezing method to achieve triaxial creep tests and strength tests at low temperatures. , but the one-way freezing process simulation of the foundation soil under the condition of atmospheric cooling cannot be realized

In 2010, Fu Wei et al. proposed a multifunctional highway soil foundation freeze-thaw cycle test device (Chinese patent number is "ZL201020254199.8"), which can realize unidirectional freezing and freeze-thaw cycles of multiple soil samples, but the The device cannot perform the corresponding mechanical strength test, and it is necessary to take out the sample after freezing and freezing-thawing cycles before performing the mechanical strength test

In 2012, Gu Tongxin et al. proposed an indoor frozen soil freeze-thaw cycle test device (Chinese patent number is "ZL201220004855.8"), which can be used to study the freeze-thaw process of soil, and obtain different temperature gradients and different soil properties. However, it is not possible to study the strength characteristics under freeze-thaw conditions.

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